Inline Cross Flow Heat Exchangers

ABSTRACT

Apparatus and methods provide for the exchange of heat in a cross flow heat exchanger having heat exchanger sub-chambers in an inline configuration. According to embodiments described herein, the heat exchanger sub-chambers may be arranged in an inline configuration, where two or more of the sub-chambers are positioned generally along a linear axis. In further configurations, to accommodate the linear configuration of two or more sub-chambers, inlet fluid flows to subsequent or downstream sub-chambers are directed to the sub-chambers using bypasses around the upstream or prior sub-chambers. Various configurations may reduce or minimize pressure losses of one or more of the fluids moving through the heat exchanger.

BACKGROUND

Heat exchangers in aircraft transfer heat energy across an energyboundary from a fluid at a higher temperature to a fluid at lowertemperature. Heat exchangers are typically categorized based on therelationship between the relative directions of the flow paths of thefluids moving through the heat exchanger. Examples of heat exchangersinclude concurrent flow (fluids move in relatively the same direction),counter flow (fluids move in opposing directions) and cross flow (onefluid flow direction is perpendicular to another fluid flow direction).The choice of heat exchanger is based on design considerations withinthe system, with each type providing various advantages and sufferingfrom various deficiencies.

Along with design considerations, the location and/or use of a heatexchanger can modify the engineering of the heat exchanger. For example,the choice and configuration of a heat exchanger used in a land-basedpower plant may have different factors than the choice and configurationof a heat exchanger used in an aircraft. In the land-based power plant,weight, size and other physical considerations may only be economicfactors, whereas in an aircraft, weight, size and other physicalconsiderations may be both economic and critical design factors.Economical operation of an aircraft relies on the costs to build andoperate the aircraft. The costs to operate the aircraft increase as thesize and weight of the mechanical components of the aircraft increase.

It is with respect to these and other considerations that the disclosuremade herein is presented.

SUMMARY

It should be appreciated that this Summary is provided to introduce aselection of concepts in a simplified form that are further describedbelow in the Detailed Description. This Summary is not intended to beused to limit the scope of the claimed subject matter.

According to one aspect of the disclosure herein, an aircraft heatexchanger is provided. The heat exchanger may include a cold fluid inputand a first partition. The first partition may split the cold fluidinput into a first cold fluid input and a second cold fluid input. Theaircraft heat exchanger may also include a hot fluid input and a secondpartition. The second partition may split the hot fluid input into afirst hot fluid input and a second hot fluid input. The aircraft heatexchanger may further include a first heat exchanger sub-chamber thatexchanges heat energy in a cross flow configuration between the firstcold fluid input and the first hot fluid input. The aircraft heatexchanger may also include a second heat exchanger sub-chamber inline tothe first heat exchanger sub-chamber. The second heat exchangersub-chamber may exchange heat energy in a cross flow configurationbetween the second cold fluid input and the second hot fluid input. Abypass may direct the second cold fluid input around the first heatexchanger sub-chamber.

According to another aspect, a method for exchanging heat betweenaircraft components is provided. The method may include receiving a coldfluid input, partitioning the cold fluid input into a first cold fluidinput and a second cold fluid input, receiving a hot fluid input,partitioning the hot fluid input into a first hot fluid input and asecond hot fluid input, exchanging heat energy in a first heat exchangersub-chamber in a cross flow configuration between the first cold fluidinput and the first hot fluid input, exchanging heat energy in a secondheat exchanger sub-chamber inline to the first heat exchangersub-chamber in a cross flow configuration between the second cold fluidinput and the second hot fluid input, and directing the second coldfluid input around the first heat exchanger sub-chamber in a bypass.

According to yet another embodiment, an aircraft is provided. Theaircraft may include an engine having a precooler fan air supply as acold fluid supply, an engine bleed air supply as a hot air supply and across flow heat exchanger. The cross flow heat exchanger may include acold fluid input for receiving the precooler fan air supply, a firstpartition for splitting the cold fluid input into a first cold fluidinput and a second cold fluid input. The cross flow heat exchanger mayalso include a hot fluid input, a second partition for splitting the hotfluid input into a first hot fluid input and a second hot fluid input.The cross flow heat exchanger may include a first heat exchangersub-chamber for exchanging heat energy in a cross flow configurationbetween the first cold fluid input and the first hot fluid input, asecond heat exchanger sub-chamber inline to the first heat exchangersub-chamber for exchanging heat energy in a cross flow configurationbetween the second cold fluid input and the second hot fluid input. Abypass may direct the second cold fluid input around the first heatexchanger sub-chamber.

The features, functions, and advantages that have been discussed can beachieved independently in various embodiments of the present disclosureor may be combined in yet other embodiments, further details of whichcan be seen with reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a conventional heat exchanger.

FIG. 2A is a perspective view of a cross flow heat exchanger, inaccordance with various embodiments presented herein.

FIG. 2B is a perspective exploded view of a cross flow heat exchanger,in accordance with various embodiments presented herein.

FIG. 3 is a top view of a cross flow heat exchanger, in accordance withvarious embodiments presented herein.

FIG. 4 is a side view of a heat exchanger mounting system, in accordancewith various embodiments presented herein.

FIG. 5 is a system diagram of a cross flow heat exchanger in use in anaircraft, in accordance with various embodiments presented herein.

FIG. 6 is a process flow diagram illustrating a method for using a crossflow heat exchanger having inline sub-chambers, in accordance withvarious embodiments presented herein.

DETAILED DESCRIPTION

The following detailed description provides for an aircraft cross flowheat exchanger having an inline arrangement. As discussed briefly above,aircraft commonly use heat exchangers to cool various aircraftcomponents, including some parts of the aircraft engine. Because weightand size can be factors when selecting and designing aircraftcomponents, the type of heat exchanger used can be limited. Because ofthose limitations, the efficiency or effectiveness of conventional heatexchangers used on aircraft may be limited, diminishing the capacity ofthe heat exchanger to adequately reduce the temperature, or in thealternative, increase the temperature, of certain fluids in theaircraft. For example, a conventional cross flow heat exchanger used toreduce the temperature of engine bleed air may be limited in its abilityto reduce the temperature to a desired temperature because of designlimitations such as size and weight. Other limitations of conventionalaircraft heat exchangers may be present as well.

Utilizing the concepts described herein, an aircraft cross flow heatexchanger is provided that, in some configurations, can achieve anincreased efficiency over conventional aircraft cross flow heatexchangers. In some configurations, the concepts described herein canprovide for a smaller heat exchanger that can achieve the same level ofcooling as a larger conventional aircraft cross flow heat exchanger. Inone configuration, concepts and technologies described herein providefor an aircraft cross flow heat exchanger having more than one crossflow heat exchange chamber in an inline arrangement. An inlet fluidflow, such as cold air from an engine, may enter an aircraft heatexchanger. The inlet fluid flow can be partitioned into severalsub-inlet fluid flows. The sub-inlet fluid flows are directed into oneor more heat exchanger sub-chambers that are arranged in an inlinepattern. As used herein, “inline” means that the central axes of one ormore sub-chambers of heat exchanger lie generally in a straight linealong an axis. The sub-inlet fluid flows exchange heat energy with across flowing fluid in their respective heat exchanger sub-chambers. Thesub-inlet fluid flows thereafter exit their respective heat exchangersub-chambers and are recombined to exit the aircraft heat exchanger asan outlet fluid flow.

As will be described below, the inline arrangement can increase theefficiency of an aircraft heat exchanger. In some configurations, bypartitioning the inlet fluid flow into sub-inlet fluid flows, with eachbeing directed to a sub-heat exchanger chamber, the pressure dropexperienced in one or both of the chambers may be reduced. By reducingor minimizing the pressure drop across any one particular component ofthe aircraft heat exchanger, the heat exchanger can be designed usingless robust materials. In some configurations, this may result inpossible weight, size and/or cost gains.

In the following detailed description, references are made to theaccompanying drawings that form a part hereof, and which are shown byway of illustration, specific embodiments, or examples. Referring now tothe drawings, in which like numerals represent like elements through theseveral FIGs., an aircraft cross flow heat exchanger having an inlinearrangement will be described.

Turning to FIG. 1, a perspective view of a conventional cross flow,fin-plate heat exchanger 100 is shown. The heat exchanger 100 has twofluid inlets, illustrated as T1 (COLD) and T2 (HOT), and two fluidoutlets, illustrated as T1 (HOT) and T2 (COLD). The T1 fluid, which maybe a gas or liquid, flows in stream 102, while the T2 fluid, which mayalso be a gas or liquid, flows in stream 104 in the heat exchangerchamber 100. It should be noted that the concepts and technologiesdescribed herein are not limited to any specific cold or hot fluidflows. Further, the use of a fin-plate heat exchanger 100 is merelyillustrative. For example, other configurations considered to be withinthe scope of the present disclosure may include configurations in whichthe T1 fluid is a hot fluid when compared to the T2 fluid.

As described above, fluids in a cross flow heat exchanger move generallynormal to each other. In a similar manner, the T1 fluid flows generallyparallel to axis XY, whereas the T2 fluid flows generally normal to axisXY. As the T1 fluid moves from inlet 106 to outlet 108, heat energy isexchanged with the T2 fluid, which is at a higher temperature than theT1 fluid. Thus, the T1 fluid exits the heat exchanger 100 at a highertemperature than when it entered the heat exchanger 100. In a similarmanner, the T2 fluid, because of the transfer of heat energy from the T2fluid to the T1 fluid, leaves the heat exchanger 100 at a lowertemperature than when it entered the heat exchanger 100.

FIG. 2A is an illustration of an inline heat exchanger 200 having inlineheat exchanger sub-chambers, according to various embodiments. In someconfigurations, the inline heat exchanger 200 can provide for increasedefficiency, reduced sized, reduced pressure drops, or other possibledesign advantages. The inline heat exchanger 200 receives as an input T1(COLD) as the lower temperature input fluid and T2 (HOT) as the highertemperature input fluid. In the configuration illustrated in FIG. 2A,the T1 (COLD) may be precooler fan air from an engine and the T2 (HOT)may be precooler bleed air. It should be appreciated that the conceptsand technologies described herein are not limited to any particularfluid source and may be equally applicable to other fluid sourceswithout departing from the scope of this disclosure and the accompanyingclaims.

The inline heat exchanger 200 has two cross flow, heat exchangersub-chambers, sub-chamber 204A and sub-chamber 204B. It should beappreciated that the concepts and technologies described herein are notlimited to any particular number of sub-chambers. Various configurationsof the concepts and technologies described herein are illustrated interms of two sub-chambers, though more may be used and are considered tobe within the scope of this disclosure. In one configuration, the heatexchange duty is shared by both sub-chamber 204A and sub-chamber 204B.It should be appreciated that the concepts and technologies describedherein are not limited to any particular division of the heat exchangeduty. For example, the heat exchange duty division between thesub-chambers 204A and 204B may be equal or one sub-chamber may beconfigured to handle more heat transfer load than the other sub-chamber.

To divide the heat exchange duties between sub-chamber 204A andsub-chamber 204B, T1 (COLD) inlet flow is partitioned into two fluidflows, illustrated as T1A (COLD) and T1B (COLD). There may be variousways in which the T1 (COLD) inlet fluid is partitioned into the T1A(COLD) and T1B (COLD) fluid flows. For example, valve 212 may beconfigured to partition the T1 (COLD) inlet flow into the T1A (COLD) andT1B (COLD) fluid flows. The value 212 may be further configured to varythe amount of fluid flow in the T1A (COLD) and T1B (COLD) fluid flows inrelation to the heat exchange duty of sub-chamber 204A and sub-chamber204B.

Another configuration for partitioning the T1 (COLD) inlet fluid intothe T1A (COLD) and T1B (COLD) fluid flows may be to use a barrier 214.The barrier 214 may be a fixed or movable divider between fluid inletchamber 216, going to sub-chamber 204A, and fluid inlet chamber 218,going to sub-chamber 204B. In some configurations in which the divisionof the T1 (COLD) inlet fluid is fixed, the barrier 214 may be a fixeddivider. In some configurations in which the division of the T1 (COLD)inlet fluid is variable, the barrier 214 may be configured to be movableto increase or decrease the amount of fluid entering fluid inlet chamber216 and fluid inlet chamber 218.

It should be understood that the valve 212 and the barrier 214, or otherfluid flow divider technologies, may be used separately or in variouscombinations. For example, the heat exchanger 200 includes both thevalve 212 and the barrier 214. T2 (HOT) inlet fluid can be split intoT2A (HOT) fluid flow and T2B (HOT) fluid flow. T2A (HOT) fluid flow canbe directed to sub-chamber 204A, while T2B (HOT) fluid flow can bedirected to sub-chamber 204B. In the cross-flow configuration of theheat exchanger 200, the T2A (HOT) fluid flow and the T2B (HOT) fluidflow can flow generally normal in sub-chambers 204A and 204B to the T1A(COLD) fluid flow and the T1B (COLD) fluid flow, respectively. Uponexiting their respective sub-chambers, T1A (HOT) and T1B (HOT), as wellas, T2A (COLD) and T2B (COLD), can thereafter be recombined into asingle fluid flow, illustrated as T1 (HOT) and T2 (COLD), respectively.

As described above, the heat exchanger 200 is in an inlineconfiguration. As illustrated in FIG. 2A, the sub-chamber 204A isgenerally inline to the sub-chamber 204B along axis AB. It should beappreciated that the concepts and technologies described herein are notlimited to any specific degree of linearity between the sub-chamber 204Aand the sub-chamber 204B, as various configurations may depart somewhatfrom a perfectly linear configuration and are still considered to bewithin the scope of the present disclosure.

In order to accommodate the cross flow pattern and the linearity of thesub-chambers 204A and 204B, the heat exchanger 200 uses a fluid flowbypass system to direct fluids around various components. In FIG. 2A,fluid bypass 220 directs the T1A (COLD) fluid flow around sub-chamber204A and into sub-chamber 204B. Fluid bypass 222 directs the T1B (HOT)fluid exiting sub-chamber 204A around sub-chamber 204B. Thus, by usingfluid bypass 220 and fluid bypass 222, the linearity of the sub-chamber204A and 204B may be achieved. Although the fluid bypass 220 and thefluid bypass 222 are shown as having generally flat or planar sidewalls,it should be understood that the fluid bypass 220 and the fluid bypass222 may be formed using various shapes, including circular, all of whichare considered to be within the scope of the present disclosure. The useof planar or rectangular components in the heat exchanger 200 is forpurposes of illustration only and does not limit the scope of thepresent disclosure or the accompanying claims to a heat exchanger usingthat particular shape.

FIG. 2B is a perspective exploded view of the heat exchanger 200illustrating an exemplary fluid flow configuration. In FIG. 2B, the heatexchanger 200 has been separated into the portions associated with thesub-chamber 204A and the sub-chamber 204B. In one implementation, thedesign of the sub-chambers 204A and 204B and their associated componentsmay resemble a chair. The wall of the fluid bypass 222 may resemble theback of a chair, which may be “offset” from the sub-chamber 204A and thearea 330 that may resemble the legs, base, or support structure. In asimilar manner, the wall of the fluid bypass 220 may be “offset” fromthe sub-chamber 204B and the area 332.

In some configurations, the “chair” design of the heat exchanger 200 mayprovide for various benefits. For example, the chair design of the heatexchanger 200 may allow for the inline of the sub-chambers 204A and 204Bwhile maintaining a relatively compact size. The bypasses 220 and 222may extend and be offset to either side along the length of thesub-chambers 204A and 204B. By placing the bypasses 220 and 222 alongthe outer walls of the sub-chambers 204A and 204B, the sub-chambers 204Aand 204B may be placed closer together and in an inline configurationthan what may be possible if the bypasses 220 and 222 were placed inanother location, such as between the sub-chambers 204A and 204B.

The shape of the bypasses 220 and 222 may also provide additionalbenefits. For example, the offset configuration of the bypasses 220 and222 may reduce the heat exchange of fluids while the fluids are in thebypasses 220 and 222. For example, if the fluid moving in the bypass 220is a hot fluid, a reduction in the temperature of the fluid will reducethe difference in temperature between the hot fluid and the cold fluidin the sub-chamber 204B, thus reducing the amount of heat exchanged withthe cold fluid. This results in a decreased efficiency of the heatexchanger 200. In a different manner, using the configuration of FIGS.2A and 2B, because the offset bypasses 220 and 222 are adjacent to thesub-chambers 204A and 204B, the fluids moving in the bypasses 220 and222 may act as insulators for the sub-chambers 204A and 204B. Forexample, hot air moving through the bypass 220 may keep colder, outsideair from interacting with the sub-chamber 204A. This may help maintainthe efficiency of the sub-chamber 204A, while reducing the amount ofinsulation needed for the sub-chamber 204A. This may allow for a smallersize of the heat exchanger 200 for a certain efficiency or heat exchangecapacity.

In some configurations, the shape of the heat exchanger 200 may alsoprovide for various fluid movement capabilities. For example, a divider334 and a divider 336, which forms part of the bypasses 220 and 222, maybe shaped to increase or decrease the velocity of fluids moving throughthe heat exchanger 200. In one implementation, the divider 334 may beshaped to cause a Venturi effect. In that implementation, the divider334 may be shaped to cause a constriction in the bypass 220, the bypass222, or both. The increased speed of the fluids may increase the heattransferred in the sub-chamber 204A, 204B, or both, an effect that maybe analogous to forced convention. In some configurations, the divider334 may be configured to cause a desired pressure drop in the fluidsmoving through the divider 334. The divider 336 may be configured toprovide benefits similar to those described in regard to the divider334. In some configurations, the divider 334 and the divider 336 may beintegral parts of the bypasses 220 and 222 and not separate structures.

In further configurations, the shape of the components of the heatexchanger 200 may provide for a modular design. As illustrated in FIG.2B, the portions associated with the sub-chamber 204A may be similar insize, shape and functionality to the portions of the heat exchanger 200associated with the sub-chamber 204B. This may allow one portion of theheat exchanger 200 to be interchangeable with another portion of theheat exchanger 200. The modular design and interchangeable nature of theconfiguration illustrated in FIG. 2B may reduce construction andassembly costs of the heat exchanger 200. For example, instead ofrequiring the design and manufacturing of different portions of the heatexchanger 200, a single portion may be designed and manufactured.Further, because of the similarity of designs, the assembly of thevarious portions of the heat exchanger 200 may be better facilitatedbecause the portions are interchangeable, obviating any errors frominstalling the incorrect portion.

In some configurations, the modular components may be modified toprovide additional benefits. For example, the divider 334 is shown inFIG. 2B as having a section 338, which is indicated by a dotted line.The section 338 may have a wall 340, which may fluidically enclose thebypass 222. The wall 340 may be used as the enclosing wall in lieu ofthe side 342 of the sub-chamber 204B. In this configuration, thedividers 334 and 336 may be abutted to provide for the heat exchanger200 with the two sub-chambers 204A and 204B. Additionally, because thebypasses 220 and 222 are enclosed by the section 338, there may not be aneed to seal the structure when assembled, as the section 338 mayprovide the fluidic barrier. A section 344 of the bypass 336 may also besimilarly configured as the section 338 of the bypass 334.

FIG. 3 is a top-down view illustrating fluid flows in a configuration ofthe presently disclosed subject matter. It should be noted that the T2(HOT) inlet fluid and the T2 (COLD) outlet fluid of FIG. 2A are notillustrated in FIG. 3. As illustrated, the T1 (COLD) inlet fluid ispartitioned into the T1A (COLD) fluid flow and the T1B (COLD) fluidflow. The T1A (COLD) fluid flow is directed to the fluid inlet chamber218 and the T1B (COLD) fluid flow is directed to the fluid inlet chamber216. In order to accommodate a linear sub-chamber configuration, the T1A(COLD) fluid flow is directed around the sub-chamber 204A by using fluidbypass 220, which directs the T1A (COLD) fluid flow through the fluidinlet chamber 218 into sub-chamber 204B. In a similar manner, the T1B(HOT) fluid flow exiting the sub-chamber 204A is directed around thesub-chamber 204B using fluid bypass 222. By using the fluid bypass 220and the fluid bypass 222, the sub-chamber 204A and the sub-chamber 204Bcan be placed generally linear along axis AB.

FIG. 4 is a side view illustrating an exemplary heat exchanger mountingsystem 400. Shown in FIG. 4 is a jet engine 424. Although the presentlydisclosed subject matter may be described in terms of a jet engine, itshould be appreciated that the technology described herein is notlimited to jet engines, as the technology may be used with other typesof engines, motors, or heat sources in general. Jet engine 424 hasprecooler fan air supply 426 as a fluid input to the sub-chamber 204Aand 204B. The precooler fan air supply 426 is a cool fluid input,similar to T1 (COLD) illustrated in FIG. 2A, above.

The mounting system 400 also includes a precooler bleed air supply 428as a second fluid input the sub-chamber 204A and 204B. The precoolerbleed air supply 428 is a hot fluid input, similar to T2 (HOT)illustrated in FIG. 2A. The precooler fan air supply 426 is heated inthe sub-chambers 204A and 204B and output as fluid 440. The precoolerbleed air supply 428 is cooled in the sub-chambers 204A and 204B andoutput as fluid 442. In some configurations, the fluid 442 can be bleedair supply to the airframe and power plant. Depending on their size, thesub-chambers 204A and 204B can be mounted close to the engine 424. InFIG. 4, the sub-chambers 204A and 204B are mounted proximate to anengine strut 444 and an aft engine mount 446. In some configurations,the sub-chambers 204A and 204B are mounted to the engine strut 444.

FIG. 5 is a system diagram illustrating an exemplary heat exchangesystem for precooling fluid for use in an aircraft. In one exemplary useof precooling for an aircraft can include an environment system for anaircraft. In some configurations, the precooler takes bleed air from theengine, such as from a compressor stage, and supplies that air to thecabin and flight deck. The bleed air is typically high pressure air at ahigh temperature. Prior to supplying various components in the aircraft,the high pressure/high temperature bleed air may need to be precooled.FIG. 5 illustrates an exemplary heat exchanger system 500 in which bleedair 502 from an aircraft engine 504 is cooled for use within anaircraft. The bleed air 502 travels from the aircraft engine 504 into awing 506 of the aircraft. The wing 506 has a top outer surface 508 and abottom outer surface 510.

As described above, components in an aircraft may be limited in sizeand/or weight based on their use in an aircraft, as illustrated by wayof example, in FIG. 5. A cross flow heat exchanger 512 is placed withinstructure components 514 and 516 of the wing 506. In someconfigurations, the structure components 514 and/or 516 may be wingspars that provide structure rigidity to the wing 506. In someconfigurations, it may be desirable or necessary to be able to place anaircraft component in the space within various structure components,such as the structure components 514 and 516. Although the concepts andtechnologies are not limited to any reason for doing so, in someconfigurations, by placing the cross flow heat exchanger 512 in thespace between the structure components 514 and 516, the integrity, andthus strength, of the structure components 514 and 516 may bemaintained. It should be noted that the cross flow heat exchanger 512may be placed in locations other than the wing 506. For example, thecross flow heat exchanger 512 may be placed in the fuselage of theaircraft. The concepts and technologies described herein are not limitedto any one location of placement of the cross flow heat exchanger 512.

The bleed air 502, which is at a high temperature and pressure, entersthe cross flow heat exchanger 512 and is split for entry into heatexchanger sub-chambers 518 and 520. As described herein, the heatexchanger sub-chambers 518 and 520 are inline. In some configurations,the inline configuration may provide for the ability of the cross flowheat exchanger 512 to be placed in certain locations in the aircraft,such as between the structure components 514 and 516. A portion of thebleed air 502 is bypassed around the heat exchanger sub-chamber 518 andis directed to heat exchanger sub-chamber 520 in a manner illustrated,by way of example, in FIGS. 2-3. Fan air 522, which is at a lowertemperature than bleed air 502, is directed into the heat exchangersub-chambers 518 and 520 and exchanges heat with the bleed air 502 intheir respective heat exchanger sub-chambers 518 and 520. The fan air522 leaves the heat exchanger sub-chambers 518 and 520 as heated fan air524 and may be recycled or used for other purposes. The precooled bleedair 502 leaves the heat exchanger sub-chambers 518 and 520 as cooledbleed air 526 for various uses such as an environmental system for theaircraft. In some configurations, the cross flow heat exchanger 512 mayminimize the pressure loss of the bleed air 502 as it is cooled.

Turning now to FIG. 6, an illustrative routine 600 for cooling anaircraft component is described in detail. Unless otherwise indicated,it should be appreciated that more or fewer operations may be performedthan shown in the figures and described herein. Additionally, unlessotherwise indicated, these operations may also be performed in adifferent order than those described herein.

Routine 600 begins at operation 602, where a cold fluid input and a hotfluid input are received at a heat exchanger. The cold fluid input canbe from various sources, including precooler fan air. The hot fluidinput can be from various sources, including precooler bleed air. Itshould be appreciated that the terms “cold” and “hot” are used only intheir relative sense and do not connote a specific temperature ortemperature range. The heat exchanger can be an inline heat exchanger inaccordance with various embodiments disclosed herein.

Routine 600 continues from operation 602 to operations 604 and 606,where the cold and hot fluids are partitioned into a plurality of fluidinputs. In one configuration, at operation 606, the cold fluid input ispartitioned into a first cold fluid input and a second cold fluid input.In a similar manner, at operation 604, the hot fluid input ispartitioned into a first hot fluid input and a second hot fluid input.It should be appreciated that the number of fluid inputs the cold and/orthe hot fluid inputs are partitioned into may vary depending on theconfiguration of the particular system. For example, a heat exchangermay have two inline sub-chambers, and therefore, the cold and the hotfluid inputs may be partitioned into a first and second fluid input. Inanother example, a heat exchanger may have n-number of inlinesub-chambers, and therefore, the cold and hot fluid inputs may bepartitioned into n-number of fluid inputs.

Routine 600 continues from operation 606 to operation 614, where thefirst cold fluid input is directed into a first heat exchangersub-chamber and the second cold fluid input is directed into a secondheat exchanger sub-chamber through a bypass around the first heatexchanger sub-chamber. In some configurations, the bypass allows for themovement of fluid around one or more of the sub-chambers while providingan inline configuration of the sub-chambers. In some configurations,providing an inline configuration may provide for a smaller heatexchanger.

Routine 600 continues from operation 614 to operation 616, where thefirst cold fluid input and the second cold fluid input are combined uponexit from their respective sub-chambers. It should be appreciated thatconcepts and technologies described herein are not limited to requiringthe combination of the fluids upon exit from their respective chambers.For example, the fluids may be further partitioned and/or may bemaintained in a separate fluid configuration. Routine 600 continues fromoperation 616 to operation 612, where the routine 600 ends.

In parallel to operation 614, the routine 600 continues from operation604 to operation 608, where the first hot fluid input is directed into afirst heat exchanger sub-chamber and the second hot fluid input isdirected into a second heat exchanger sub-chamber. The routine 600continues from operation 608 to operation 610, where the first hot fluidinput and the second hot fluid input are combined upon exit from theirrespective chambers. It should be appreciated that concepts andtechnologies described herein are not limited to requiring thecombination of the fluids upon exit from their respective chambers.Routine 600 continues from operation 610 to operation 612, wherein theroutine 600 ends.

Based on the foregoing, it should be appreciated that technologies forexchanging heat in an aircraft cross flow heat exchanger having inlineheat exchanger sub-chambers have been presented herein. The subjectmatter described above is provided by way of illustration only andshould not be construed as limiting. Various modifications and changesmay be made to the subject matter described herein without following theexample embodiments and applications illustrated and described, andwithout departing from the true spirit and scope of the presentdisclosure, which is set forth in the following claims.

1. An aircraft heat exchanger, comprising: a cold fluid input; a firstpartition that splits the cold fluid input into a first cold fluid inputand a second cold fluid input; a hot fluid input; a second partitionthat splits the hot fluid input into a first hot fluid input and asecond hot fluid input; a first heat exchanger sub-chamber thatexchanges heat energy in a cross flow configuration between the firstcold fluid input and the first hot fluid input; a second heat exchangersub-chamber inline to the first heat exchanger sub-chamber such that afirst central axis of the first heat exchanger sub-chamber along adirection of the first cold fluid input and a second central axis of thesecond heat exchanger sub-chamber along a direction of the second coldfluid input lie generally in a straight line along a common axis, thesecond heat exchanger sub-chamber exchanges heat energy in a cross flowconfiguration between the second cold fluid input and the second hotfluid input; and a bypass that directs the second cold fluid inputaround the first heat exchanger sub-chamber and into the second heatexchanger sub-chamber.
 2. The aircraft heat exchanger of claim 1,wherein the cold fluid input comprises precooler fan air from an engine.3. The aircraft heat exchanger of claim 1, wherein the hot fluid inputcomprises bleed air from an engine.
 4. The aircraft heat exchanger ofclaim 1, wherein the first partition comprises a valve having aplurality of outputs that split the cold fluid input into the first coldfluid input and the second cold fluid input.
 5. The aircraft heatexchanger of claim 1, wherein the first partition comprises a barrierthat splits the cold fluid input into the first cold fluid input and thesecond cold fluid input.
 6. The aircraft heat exchanger of claim 1,wherein the second partition comprises a valve having a plurality ofoutputs or a barrier that splits the hot fluid input into the first hotfluid input and the second hot fluid input.
 7. A method for exchangingheat between aircraft components, the method comprising: receiving acold fluid input; partitioning the cold fluid input into a first coldfluid input and a second cold fluid input; receiving a hot fluid input;partitioning the hot fluid input into a first hot fluid input and asecond hot fluid input; exchanging heat energy in a first heat exchangersub-chamber in a cross flow configuration between the first cold fluidinput and the first hot fluid input; exchanging heat energy in a secondheat exchanger sub-chamber inline to the first heat exchangersub-chamber in a cross flow configuration between the second cold fluidinput and the second hot fluid input; and directing the second coldfluid input around the first heat exchanger sub-chamber in a bypass thatis offset to a side of the first heat exchanger sub-chamber, extendsalong a length of the first heat exchanger sub-chamber, and enters thesecond heat exchanger sub-chamber positioned such that a first centralaxis of the first heat exchanger sub-chamber and a second central axisof the second heat exchanger sub-chamber lie generally in a straightline along a common axis.
 8. The method of claim 7, wherein the coldfluid input comprises precooler fan air from an engine.
 9. The method ofclaim 7, wherein the hot fluid input comprises precooler bleed air froman engine.
 10. The method of claim 7, wherein partitioning the coldfluid input into the first cold fluid input and the second cold fluidinput comprises directing the cold fluid input into a valve having aplurality of outputs.
 11. The method of claim 7, wherein partitioningthe cold fluid input into the first cold fluid input and the second coldfluid input comprises directing the cold fluid input through a barrierconfigured to split the cold fluid input into the first cold fluid inputand the second cold fluid input.
 12. The method of claim 7, furthercomprising combining a hot output of the first heat exchangersub-chamber and a hot output of the second heat exchanger sub-chamber.13. The method of claim 7, further comprising combining a cold output ofthe first heat exchanger sub-chamber and a cold output of the secondheat exchanger sub-chamber.
 14. The method of claim 7, furthercomprising combining the first hot fluid input and the second hot fluidinput upon exiting the first heat exchanger sub-chamber and the secondheat exchanger sub-chamber, respectively.
 15. An aircraft, comprising:an engine having a precooler fan air supply; and a cross flow heatexchanger comprising a cold fluid input for receiving the precooler fanair supply; a first partition for splitting the cold fluid input into afirst cold fluid input and a second cold fluid input; a hot fluid input;a second partition for splitting the hot fluid input into a first hotfluid input and a second hot fluid input; a first heat exchangersub-chamber for exchanging heat energy in a cross flow configurationbetween the first cold fluid input and the first hot fluid input; asecond heat exchanger sub-chamber inline to the first heat exchangersub-chamber for exchanging heat energy in a cross flow configurationbetween the second cold fluid input and the second hot fluid input; anda bypass for directing the second cold fluid input around the first heatexchanger sub-chamber, the bypass having a wall in contact with thesecond cold fluid input of a height equivalent to a height of the firstheat exchanger sub-chamber and configured to divide the second coldfluid input within the bypass on a first side of the wall from the firstcold fluid input and the first hot fluid input within the first heatexchanger sub-chamber on a second side of the wall.
 16. The aircraft ofclaim 15, wherein the hot fluid input comprises bleed air from anengine.
 17. The aircraft of claim 15, wherein the first partitioncomprises a valve having a plurality of outputs that split the coldfluid input into the first cold fluid input and the second cold fluidinput.
 18. The aircraft of claim 15, wherein the first partitioncomprises a barrier that splits the cold fluid input into the first coldfluid input and the second cold fluid input.
 19. The aircraft of claim15, wherein the second partition comprises a valve having a plurality ofoutputs or a barrier that splits the hot fluid input into the first hotfluid input and the second hot fluid input.
 20. The aircraft of claim15, wherein a cross flow heat exchanger is mounted proximate to anengine strut.